Portable heating devices have been utilized to raise the temperature in a living space for many years. Conventional portable forced hot air heaters for consumer use are well-known and are comprised of an electrical heating element and a fan within a housing. Ambient air is forced to pass through or over the heating element thus raising the temperature of the air. As sufficient air passes through the heating element the ambient temperature of the room is raised as desired.
One type of conventional portable heater is normally low in elevation with respect to a support surface, such as the floor. This low profile increases the distance that the heat must travel (i.e., the heat path) to reach the upper trunk of the users body. The added heat path distance does not produce the desired effect of heating the upper trunk and extremities of the user body efficiently.
Another type of conventional heater utilizes a transverse air impeller assembly. This type of heater attempts to raise the exit height of the hot air exhaust stream with respect to the floor. One drawback of this type of air circulator is that transverse air impeller assemblies typically have several sections which must be coupled together by glue or ultrasonic welding. This assembly must then be balanced to insure correct operation. Transverse air impeller assemblies may also necessitate the use of vibration dampers on the motor. In addition, long transverse air impeller assemblies tend to become misaligned, thereby requiring a special bearing mounted in rubber pads to compensate for the misalignment. The above mentioned problems are exacerbated as the length of the transverse air impeller assembly is increased, which limits the elevation that the heated exhaust stream can be raised above the floor with a conventional tower heater design. These features and associated problems also add significant expense to the manufacturing process. The result is translated into a higher retail price and less desirable comfort levels for the consumer.
Conventional heaters that utilize a centrifugal blower assembly encounter similar manufacturing problems when the impeller length is increased. Shaft length of the motor, impeller balancing and the need for a more powerful motor to rotate the longer impeller increase manufacturing costs. These problems all result in higher retail prices for heaters having long centrifugal blower assemblies.
The design of conventional tower heaters therefore limits the vertical height of the heated exhaust air stream. This is caused, in part, because the cost and complexity of the devices increases as the length of the heating element and/or the length of the impeller increases.
In light of the aforementioned problems there is a need for a forced air heater having a heated exhaust air stream at a height sufficient to shorten the heat path to an upper portion of the user's body. This heating device should have a vertical aspect ratio while using an air generator with an impeller design having the desired air flow characteristics that allow ease of manufacturing and a desirable retail cost for the consumer.